Copa is in the Star Alliance. I consider it a discount airline, and they fly mainly narrow-body aircraft, even on international routes. I know people who have taken them and NOT had a good experience, though I don't know the details excpet for one friend who took them Biz Class from Braizl to the U.S. and back and found he servie so-so and things a bit chaotic at times (e.g., those form economy class lining up to use the biz class rest rooms). But, then, he was paying much less than he would have in biz class on other carriers. And since you're flying to Panama, I assume they have the most direct routes.

Do you mean their fare is "competitive" with others you've found or are cheaper? What are your other options? Considering time and money involved, Copa may be your best choice. Non-stop from Chicago vs. having to connect with a different carrier would probably be an easy choice for me.